Florida's immigrant workers, documented and undocumented, once were visible only in our fields and groves. No more. Even the most casual observer can't help notice more Mexicans and Latin Americans among airport and office cleaners, construction workers, highway maintenance personnel and roofing crews. Here in the building that houses Florida Trend's offices, a crew from a local, well-established construction firm has been doing some renovation work; aside from the foreman, the workers appear much more likely to have their origins in Chihuahua than Pinellas Park.

According to the Urban Institute Immigration Studies Program, about a quarter of the total foreign-born population of the country are undocumented immigrants. In Florida, that translates into nearly a million workers who are here, either full or part time, without proper documents. Somewhere between a third and 40% are women.

This has never been much of an issue for many employers, whose need for unskilled labor continues to trump scruples about paperwork despite a beefed up law requiring them to check. A phony driver's license (the going rate is about $1,500) or something that looks even vaguely like a Social Security card still gets you on the job.

And while the general public tells pollsters they're aghast at the nation's porous borders and the influx of foreign workers, the pollsters never seem to ask how much more people would be willing to pay -- or how long they'd be willing to wait -- to have their roof installed or hotel bed made or tomatoes picked, by an American citizen. That, of course, assumes American citizens would respond to ads for those jobs.

There is something relentlessly supply-and-demand about the presence of immigrant workers. They come because there are jobs available. They have to travel thousands of miles, typically live in crowded, lousy, overpriced housing, have few legal rights, are cheated out of pay by employers or crew chiefs, cope with the communication and cultural barriers inherent in living and finding work in a foreign land, and often do work that's unpleasant or dangerous. Yet despite all those risks and transaction costs, the essential truth is that the effort makes economic sense for them and their families. They're able both to support themselves here and send money home.

Meanwhile, with an unemployment rate of about 3.5% in Florida, it's very tough to argue that they're taking jobs away from American citizens or even depressing wages. It's easier to imagine a motel closing than it is to imagine it ever paying its maids $17 an hour with benefits.

Some of the immigration reform legislation now in Congress almost makes a good case for leaving alone the current "don't-ask-don't-tell-don't-enforce'' policy. Three U.S. senators (one Democrat, two Republicans) actually proposed building a 1,900-mile fence along the Mexican border complete with "roads, lighting and sensors" -- a great use of a billion dollars' worth of taxpayers' money assuming no enterprising workers in Mexico can find a boat or plane.

But there are good reasons for the country to take a different approach. For one, the sheer number of immigrant workers -- and their increasing visibility and necessity -- makes the issue more immediate. A few months ago, the Associated Press reported that construction on a new federal building in Orlando came to a screeching halt after a roundup of immigrant workers with phony Social Security cards depleted the construction crew.

Another reason for immigration reform is that in the wake of Sept. 11 the country has real concerns about secure borders and its ability to track those from abroad who live and work here -- if we can't control the influx of people who want to come here to work, what kind of confidence can we have in our ability to keep out destructive elements?)

Yet another reason comes from Barbara Mainster, executive director of the Redlands Christian Migrant Association, a 40-year-old group that provides child-care and other services to the children of immigrant workers. "It's not morally right" that people who come here to work hard -- and are offered employment by American companies -- should have to exist in the shadows, she says. "How can we call ourselves a great leader when we treat people this way?"

We don't have to make everyone an American citizen, she says. "Citizenship is not the issue. Legal status is the issue ... their ability to work in this country. They simply want to be able to do legally what they're doing already."

Plenty of business interests get it. The Florida Farm Bureau and the Florida Fruit and Vegetable Growers, for example, both backed President Bush's proposal for a guest worker program that would create legal status for immigrant workers. Groups like builders and construction interests and the tourism industry need to get behind some kind of worker visa program along with the others. They have the same economic and moral interests as the agricultural businesses in ensuring their workers are documented. Joel Adams, president of the Polk County Builders Association, told the Lakeland Ledger that an influx of Hispanic workers had sustained the county's building boom. "It was a godsend. We were struggling to find reliable help," he said.

As long as there is work, workers will come -- from somewhere. Economist Lester Thurow, in a speech that's now about a decade old, said that one of the economic "tectonic plates" that's reshaping world economies is mass migration from poor countries to rich countries. "For the first time in human history everybody knows what standards of living are elsewhere in the world. Why should you sit in a village where the per capita income is $200, when you know that there are places where the per capita income is $30,000 and all you have to do is get up and walk?"

It's worthwhile keeping Thurow's image of tectonic plates in mind. Immigrant workers may have to come many miles to get here, but trends in the world mean the economic ground is moving under all our feet.You can reach Mark Howard at mhoward@floridatrend.com